terminal - creating a new screen (like vi and less does) in a textual program -

programs vi, less, screen, when executed, fill terminal data, , then, if press c - z (or terminate program) terminal return before execution of these programs.

how program that? correct terminology kind of thing?

ps: words used in title may not correct since i've no idea terminology of kind of things.

edit: thank @atropo know correct name of these foreground process, but, how program that? how program can clear screen, writing and, @ end of execution, let shell reappear old writings?

they're called foreground processes.

usually foreground processes show user interface, through user can interact program. user must wait 1 foreground process complete before running one. while use foreground process shell prompt disappears until close process or put in background.